If something smells fishy the next time you step up to the seafood counter or sit down for sushi, it may not be the catch of the day. An estimated 33 percent of seafood sold in the United States is incorrectly labeled by type of fish, catch method or provenance, according to a recent report by conservation group Oceana. So that ahi tuna roll you ordered might actually be escolar, a cheaper substitute known as the 'ex-lax fish' for its digestive effects, and the wild-caught shrimp at the grocery store could have in fact been farm-raised in Thailand.

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This is not a new problem—there have been documented cases going back to at least the 1930s when canneries tried to pass off mackerel for pricier salmon. But now, with the falling price of computing power and tech-enabled tracking devices starting to change traceability methods, technology is fast-becoming an unlikely hero in the traditional world of seafood.

The seafood industry's notoriously opaque supply chains mean that exactly how, and how often, fish mislabeling occurs is not precisely known. In Oceana's two-year test of 1,200 fish samples in 21 states, one-third were found to be fraudently labeled. While the organization admits the report was never meant to be a scientific survey and the actual scale of the problem is not perfectly understood, it is clear that there are plenty of opportunities for mislabeling to occur on seafood's journey from the water to your plate.

"There are 101 different root causes for this," said Gib Brogan, fisheries campaign manager at Oceana, and no one is sure which parts of the supply chain are the most likely points for mislabeling to occur. "But what it comes down to is trying to find value for the fish," he said. Distributors, fishmongers or others that handle the fish along the supply chain might be trying to get a higher price for a low-valued fish, sell an overfished species or sell one that is out of season.